Temperature control device



March 23, 1948. F. D. BENNETT E! AL TEMPERATURE CONTROL DEVICE FiledJune 3, 1944 2 Sheets-Sheet 1 FIG. I

FIG.3

FIG. 4

K nm M m T W M 7 E V W M KQA r K 1m CS l! mA 4 EM I DO M FT Y March 23,1948. 1:; BENNETT ET'AL 2,438,109

TEMPERATURE CONTROL DEVICE Filed June 3, 1944 2 Sheets-Sheet 2'INVENTOR. FREDERICK D.BENNETT BYTHOMAS A. NEWKIRK FIG.5

Potented Mar. 23, 1948 TEMPERATURE CONTROL DEVICE .Frederick D. Bennett,Dayton, and Thomas A.

Ncwkirk, Fairilcld, Ohio Application June 3, 1944, Serial No. 538,876

1 Claim.

(Granted under the m of March a, me, as amended April 80, 1928; 370 0.G. 757) The invention described herein may be manufactured and used byor for the Government for governmental purposes, without the payment tous of any royalty thereon.

The invention to be hereinafter described relates to temperatureactivated couples for controlling switch operation.

It is common practice to control the operations of switches, valves andother devices by bimetallic couples in which the two metallic elements,having diii'erent coefllcients of expansion, apply that difference tocontrol the operation; One reat objection to such bimetallic couples isthat they frequently produce chattering or irregular action. The presentinvention completely eliminates this serious objection and, at the sametime, provides a simple, compact, economical and highly eflicientpositively acting couple.

In order to more clearly disclose this construction, operation and useof the invention, reference should be had to the accompanying drawingsforming part of the present application. Throughout the several figuresof the drawings like reference characters designate the same parts inthe different views.

In the drawings:

Fi 1 is a front elevation;

Fig. 2 is a top planview of Fig. 1, top of casing being indicated indotted lines;

Figs. 3 and 4 are, respectively, enlarged fragmentary front elevationsof the end portions of Fig. 1, Fig. 3 being partly broken away; and

Figs. 5 and 6 are cross sections on lines 5-5 and 86, respectively, ofFigs. 3 and 4 respectively.

Referring to the drawings in detail, I is a suitable box-like casing orframe, preferably of aluminum. As shown, this case is substantiallyrectangular and shallow, though both the sha and dimensions may varyconsiderably within a considerable range. Within this caseis disposed aninto the rear wall of the casing at a point a short distance from theelbow or bend. Due to this connection, movement of easing I, due totemperature change, either expansion or contraction, will carry lever 2with it. That, of course, will cause no movement of lever 2, relative tocasing I. In

the lower part of the casing below and approximately parallel with thelong arm of lever I, is a porcelain rod 4 of substantially the samelength as the long arm of 2. It is positively anchored, at one end, tothe corresponding end of casing l and therefore, moves only by and withthat end of the casing. The coeflicient of expansion of porcelain is, ofcourse, difierent and much lower than that of aluminum. In assembledrelation, with rod 4 and the long arm of 2 approximately parallel, oneend of rod 4 just contacts the adiacent face of the lower end of theshort arm of 2. In that position, if there were no connection between 2and 4, expansion of l due to increase of temperature could simply carry2 with it away from theadjacent end of 4. By definitely anchoring theend of l to the adjacent end of the short arm of 2 by a screw 8 passedthrough it and into the end of l, the rod 4 acts as a stop or anchor,preventing the free travel of the lowerend of that short arm with thecasing I. Since rod 4 elongates less than casing I for the same rise intemperature, this connection will cause lever 2 to rock on its pivot 3,raising the free end of the long arm of 2 from the push button or pin 5of a well known type of micro-switch 8 suitably mounted in well knownmanner in casing i. This, in turn, will make or break, as may bedesired, the circuit controlled by the micro-switch. For adjusting themicro-switch to operative position where it will be activated by lever2, the threaded rod 9 through aluminum block I0, is provided.

In order to provide the necessary free rocking movement of thecontacting ends of l and 2, the end of 2, both where it contacts 4 andwhere it contacts screw 8 is curved or rounded as at 1.

While porcelain and aluminum have been particularly set forth asmaterials involved in the couple of this invention. the invention is notlimited specifically to them. They have been found to eliminate thechatter objection found in bimetallic couples. Other non-metallicmaterials such as certain plastics for instance, may be used in place ofporcelain, the essential being the relative coeilicient of expansion asbetween such selected material and the metallic material used and therelative characteristics of their expansions.

Many changes may be made in the construction, arrangement anddisposition of the various parts of the invention, within the scope ofthe appended claim, without in any degree departing from the fieldthereof and it is meant to include all such within the applicationwherein only one preferred form has been disclosed by way ofiiiustration and with no thought or intention o! limiting the inventionthereby.

Having thus described our invention, what we claim and desire toprotect-by Letters Patent is:

In a device of the character described, a metallic case, a bell-cranklever carried by said case and pivotally mounted therein, a rod having acoeflicient of expansion difl'erent than that or said case and anchoredat one end to that end of the case remote from the lever pivot, one endof said lever having opposed convex surfaces one 91' which contacts thefree end of the rod and adjustable, threaded fastening means passingthrough said convex surfaces into said rod, said fastening means beingloose enough to allow continuous, tree-sliding. rocking, surface-contactof the lever on-and between said rod and fastening means.

FREDERICK D. BENNE'I'I'.

THOMAS A. NEWKIRK.

4 nmnncns 01m The iollowing references are 0! record in the file of thispatent:

5 UNITED STATES PATENTS Number Name Date 1,075,991 Ruud Oct. 14,19131,111,789 Freas Sept. 29, 1914 1,703,283 Smith Feb. 28, 1929 1,857,025Hurxthal. May 3, 1032 2,033,410 Dezotell Mar, 10, 1936 2,080,661 HillMay 18, 1937 2,185,623, Beam Jan, 2, 1940 15 FOREIGN PATENTS NumberCountry Date 53,709 Germany Oct. 1, 1890 466,477 Germany Mar. 13, 1926700,112 France .....1 Dec. 22, 1930

